1. Field of the Invention
The present invention relates to a server apparatus, a communication terminal apparatus, a delivery system, and a delivery program that perform a delivery service via a network.
2. Description of the Related Art
Conventionally, delivery services that transmit various types of data from a server apparatus via a network to a communication terminal apparatus on the user side have been performed. When performing such services, authentication of the users is performed in some cases. For example, when a delivery service is received by a personal computer connected via the Internet, user authentication can be performed without complicated operations if the server apparatus has a terminal apparatus automatically transmit and receive a cookie that is stored by a browser.
However, in the above conventional authentication method, from the user's viewpoint, a unique user ID and a variety of information are automatically transmitted, so that there has been the problem that while the connection procedure is simplified, the user's privacy is decreased without exception and security is low.
A user who wishes to remain anonymous can receive the provision of a service with his or her anonymity maintained by making a desired selection from a menu displayed on a website every time the user connects, for example. However, the input operation that needs to be performed in such a case is both difficult to understand and troublesome.
On the other hand, depending on the type of data to be delivered, it may not be especially necessary for the server side to authenticate the user. Where user authentication is strictly performed for all users, the users of a service will be excessively restricted, which hinders the widespread use of the service.